All requests arriving for processing after OFFLINE flag set are rejected
with BUSY status. Races around OFFLINE flag setting are closed by calling
taskqueue_drain_all().
CTL HA functionality was originally implemented by Copan many years ago,
but large part of the sources was never published. This change includes
clean room implementation of the missing code and fixes for many bugs.
This code supports dual-node HA with ALUA in four modes:
- Active/Unavailable without interlink between nodes;
- Active/Standby with second node handling only basic LUN discovery and
reservation, synchronizing with the first node through the interlink;
- Active/Active with both nodes processing commands and accessing the
backing storage, synchronizing with the first node through the interlink;
- Active/Active with second node working as proxy, transfering all
commands to the first node for execution through the interlink.
Unlike original Copan's implementation, depending on specific hardware,
this code uses simple custom TCP-based protocol for interlink. It has
no authentication, so it should never be enabled on public interfaces.
The code may still need some polishing, but generally it is functional.
Relnotes: yes
Sponsored by: iXsystems, Inc.
This is preparation for possibility to open/close media several times
per LUN life cycle. While there, rename variables to reduce confusion.
As additional bonus this allows to open read-only media, such as ZFS
snapshots.
It has nothing to share with too huge ctl.c other then device descriptor,
but even that may be counted as design error that may be fixed later.
At some point we may even want to have several ioctl ports.
Its idea was to be a simple initiator and execute several commands from
kernel level, but FreeBSD never had consumer for that functionality,
while its implementation polluted many unrelated places..
Reporting SCSI errors to console is often useless, pollutes logs and may
affect performance. For debugging there is kern.cam.ctl.debug sysctl
MFC after: 1 week
At this point IMMED flag is translated to MNT_NOWAIT flag of VOP_FSYNC(),
hoping that file system implements that (ZFS seems doesn't).
MFC after: 2 weeks
Sponsored by: iXsystems, Inc.
Before this change SYNCHRONIZE CACHE commands were executed exclusively,
as if they had ORDERED tag. But looking through SCSI specs I've found
no any reason to be so strict. For reads this ordering seems pointless.
For writes it looks less obvious, so I left ordering against preceeding
write commands, while following ones are no longer required to wait.
MFC after: 2 weeks
Sponsored by: iXsystems, Inc.
During vMotion and Clone VMware by default runs multiple sequential 4MB
XCOPY requests same time. If CTL issues reads sequentially in 1MB chunks
for each XCOPY command, reads from different commands are not detected
as sequential by serseq option code and allowed to execute simultaneously.
Such read pattern confused ZFS prefetcher, causing suboptimal disk access.
Issuing all reads same time make serseq code work properly, serializing
reads both within each XCOPY command and between them.
My tests with ZFS pool of 14 disks in RAID10 shows prefetcher efficiency
improved from 37% to 99.7%, copying speed improved by 10-60%, average
read latency reduced twice on HDD layer and by five times on zvol layer.
MFC after: 2 weeks
Sponsored by: iXsystems, Inc.
Previously several places were doing it on its own, partially
incorrectly (e.g. without the filedesc locked) or even actively harmful
by populating jdir or assigning rootvnode without vrefing it.
Reviewed by: kib
To avoid conflicts between target and initiator devices in CAM, make
CTL use target ID reported by HBA as its initiator_id in XPT_PATH_INQ.
That target ID is known to never be used for initiator role, so it won't
conflict. For Fibre Channel and FireWire HBAs this specific ID choice
is irrelevant since all target IDs there are virtual. Same time for SPI
HBAs it seems could be even requirement to use same target ID for both
initiator and target roles.
While there are some more things to polish in isp(4) driver, first tests
of using both roles same time on the same port appeared successfull:
# camcontrol devlist -v
scbus0 on isp0 bus 0:
<FREEBSD CTLDISK 0001> at scbus0 target 1 lun 0 (da20,pass21)
<> at scbus0 target 256 lun 0 (ctl0)
<> at scbus0 target -1 lun ffffffff (ctl1)
- remove last remnants of never implemented multiple targets support;
- implement missing support for LUN mapping in this area.
Due to existing locking constraints LUN mapping code is practically
unlocked at this point. Hopefully it is not racy enough to live until
somebody get idea how to call sleeping fronend methods under lock also
taken by the same frontend in non-sleepable context. :(
At this point CTL has no known use case for device queue freezes.
Same time existing (considered to be broken) code was found to cause
modify-after-free issues.
Discussed with: ken
MFC after: 1 week
This change by 2-3 times improves performance of misaligned XCOPY and WUT
commands by avoiding unneeded read-modify-write cycles inside ZFS.
MFC after: 1 week
This change by 2-3 times improves performance of misaligned WRITE SAME
commands by avoiding unneeded read-modify-write cycles inside ZFS.
MFC after: 1 week
target iSCSI offload. Add mechanism to query maximum receive data segment
size supported by chosen hardware offload module, and use it in ctld(8)
to determine the value to advertise to the other side.
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
While ctld(8) still does not allow multiple portal groups per target
to be configured, kernel should now be able to handle it.
MFC after: 2 weeks
Sponsored by: iXsystems, Inc.
Replace iSCSI-specific LUN mapping mechanism with new one, working for any
ports. By default all ports are created without LUN mapping, exposing all
CTL LUNs as before. But, if needed, LUN mapping can be manually set on
per-port basis via ctladm. For its iSCSI ports ctld does it via ioctl(2).
The next step will be to teach ctld to work with FibreChannel ports also.
Respecting additional flexibility of the new mechanism, ctl.conf now allows
alternative syntax for LUN definition. LUNs can now be defined in global
context, and then referenced from targets by unique name, as needed. It
allows same LUN to be exposed several times via multiple targets.
While there, increase limit for LUNs per target in ctld from 256 to 1024.
Some initiators do not support LUNs above 255, but that is not our problem.
Discussed with: trasz
MFC after: 2 weeks
Relnotes: yes
Sponsored by: iXsystems, Inc.
sys/cam/scsi/scsi_all.h:
In struct scsi_extended_inquiry_data:
- Increase the length field to 2 bytes, as it is 2 bytes in SPC-4.
- Add bit definitions for the various Activiate Microcode actions.
- Add the Sequential Access Logical Block Protection support bit,
since we need that in the sa(4) driver. (For modifications
that will come later.)
- Add definitions for the various Multi I_T Nexus Microcode
Download modes.
sys/cam/ctl/ctl.c:
As of SPC-4, a single report of "REPORTED LUNS DATA HAS CHANGED"
is to be given per I_T nexus. Once it is reported, the unit
attention condition should be cleared for all LUNS attached to
an I_T nexus.
Previously that only happened when a REPORT LUNS command was
processed.
This behavior may be different (according to SAM-5) when the
UA_INTLCK_CTRL bits are non-zero in the control mode page but
CTL does not currently support that.
So, in view of the spec, whenever we report a LUN inventory
change unit attention, clear it on all LUNs for that
particular I_T nexus.
Add a new function, ctl_clear_ua() that will clear a unit
attention on all LUNs for the given I_T nexus.
One field in the extended inquiry data that we could potentially
report at some point is the maximum supported sense data length.
To do that, we would the SIM to report (via path inquiry
perhaps) how much sense data it is able to send.
Add comments to explain some of the bits that are set in the
Extended Inquiry VPD page.
Add a few comments to make it more clear which functions handle
various VPD pages.
Sponsored by: Spectra Logic
MFC after: 1 week
This could cause data corruption due to accessing wrong LUN in case of
retries on write errors. Failed writes were retried to read LUN.
MFC after: 3 days
